Abstract This paper presents a methodology for quantitatively assessing energy security. The methodology is tailored to suit the limited data availability of Malaysia and other Southeast Asian countries. In this methodology, energy security is conceptualized as having 5 core aspects which sub-divide into 13 elements. A total of 35 indicators have been identified as measurements of these 13 elements. The methodology details the means by which the indicator results are converted into a common unit i.e. a normalization process into a 0-to-1 scale. Also detailed are the weights used in the weighted-average process by which normalized indicators are synthesized into composite scores representing the 13 elements, the 5 core aspects, and 1 overall energy security index.